Amine-loaded sepiolite/carbon aerogels engineered with conductive frameworks for efficient direct air capture and solar/electric-thermal desorption

[Geoengineering News]

https://www.sciencedirect.com/science/article/abs/pii/S2213343726026667

Authors: Jie Wang, Shuai Wang, Fanshu Ding, Sijin Dong, Changrui Shi et al.

20 June 2026

https://doi.org/10.1016/j.jece.2026.123691

Highlights

•Aerogels form via chitosan-gelled sepiolite with uniformly dispersed nanocarbon.

•Nanocarbon type defines conductive networks essential for efficient regeneration.

•Amine loading, humidity, and flow rate affect CO2 capture under ambient conditions.

•Monolithic sorbents show efficient CO2 uptake and solar/electric-thermal desorption.

Abstract

Direct air capture (DAC) has emerged as a promising negative-emission technology to mitigate the continuous accumulation of atmospheric carbon dioxide (CO2). Nevertheless, its widespread implementation is currently hindered by the high cost of adsorbents and the dependence on fossil fuel-derived thermal energy for regeneration. Therefore, the development of low-cost, high-performance sorbents with energy-efficient regeneration is urgently required. In this work, we report a polyethyleneimine-impregnated composite aerogel based on natural sepiolite, nanocarbon, and chitosan for efficient CO2 capture from air and renewable-energy-driven regeneration via photothermal and electrothermal pathways. Sepiolite nanofibers act as the structural scaffold, enabling uniform dispersion of carbon materials and providing abundant anchoring sites for amines. This design substantially reduces production costs while delivering high CO2 uptake and excellent dual-mode regeneration performance using renewable energy. Systematic investigation of amine loading, relative humidity, and gas flow rate revealed that the optimized SCCP-40% sample achieves an outstanding CO2 uptake of 2.86 mmol/g under 400 ppm CO2 and 60% RH. Moreover, the aerogel heats to 76 °C within 10 min under 1 sun and to 80 °C within 30 s at 0.3 W, enabling over 70% CO2 desorption within 20 min. These outstanding performances are mainly attributed to the well-dispersed sepiolite nanofibers and conductive frameworks with nanocarbon, which facilitate the efficient transfer of photothermal and electrothermal for CO2 desorption. The amine-loaded sepiolite/carbon aerogels developed here offer a low cost, high adsorption performance, and energy-flexible regeneration, providing a novel and practical strategy for the design of advanced DAC adsorbents with engineering potential.

Source: ScienceDirect